It's ironic that the worst episode of the entire series is followed by one of the best episodes (How Your Mother Met Me). I really enjoyed the end, but i have to agree with those who say that the 9 season of this amazing show almost ruined the show itself. And it's so sad because a show its always remembered by its final season, in my point of view. It was a wasted episode. The authors should have used this time to show us a little more about the mother, a little more about her relationship with Ted. The criticism around the final episode is, at least the most part of it, around the short time of Mother's life on screen. In sum: unfunny, wasted time, boring episode.
